There have been a wide variety of apparatus in the prior art which were designed for dispensing granular materials, such as coffee. In general, these prior art devices dispense product into a hopper or similar apparatus which will hold a predetermined volume of material. This hopper is then utilized to dispense the predetermined quantity of material to the consumer. Examples of this type of device may be found in U.S. Pat. No. 4,053,087 to Lack et al., U.S. Pat. No. 4,998,648 to Contreras, U.S. Pat. No. 5,292,037 to Held, U.S. Pat. No. 5,421,491 to Tuvim et al., and U.S. Pat. No. 5,437,396 to Russillo et al.
In order to provide the dispenser with the capability of dispensing variable quantities of product, a number of mechanisms were developed to provide a hopper with an adjustable volume. Examples of such devices may be found in U.S. Pat. No. 4,130,149 to Hausam, U.S. Pat. No. 4,162,751 to Hetland et al., U.S. Pat. No. 4,394,940 to Peterson, U.S. Pat. No. 4,569,463 to Pellegrino, and U.S. Pat. No. 5,375,744 to Henderson.
While all of these devices were capable of fulfilling their intended purposes, they still suffer several drawbacks. First, the dispensing process was a two-step process, requiring the distribution of a quantity of product into a hopper, and then a second step of dispensing the contents of the hopper to the consumer. This two-step process complicates the mechanism, and increases the cost to produce the device.
In addition, many of the devices either require more than one hopper, of varying size, or a complicated variable volume hopper, in order to distribute a variety of different volumes of product. Again, the use of a plurality of hoppers, or the use of a variable volume hopper, required complicated apparatus to achieve its purpose. Thus, the prior art devices tended to be relatively expensive to produce and maintain.